Wearable radar reflectors

Abstract

A wearable radar reflector includes a retroreflector configured to reflect radiation received from a vehicle, and incorporated into a garment worn by a pedestrian.

What is claimed is: 
     
         1 . A radar identification device, comprising:
 a memory configured to store demographic information for a user; and   a radar retroreflector, configured to be worn or carried by the user and further configured to modulate a retroreflected radar signal in the frequency range of about 1 to about 300 GHz with at least a subset of the stored demographic information.   
     
     
         2 . The device of  claim 1 , wherein the memory is configured to update the stored demographic information. 
     
     
         3 . The device of  claim 1 , wherein the memory is configured to be worn or carried by the user. 
     
     
         4 . The device of  claim 1 , wherein the radar retroreflector is configured to select what demographic information to include in the modulated retroreflected radar signal. 
     
     
         5 . The device of  claim 1 , wherein the radar retroreflector is a first radar retroreflector, the device further comprising a second radar retroreflector configured to be worn or carried by the user. 
     
     
         6 . The device of  claim 5 , wherein the first radar retroreflector and the second radar retroreflector are configured to produce the same modulated retroreflected radar signal. 
     
     
         7 . The device of  claim 5 , wherein the first radar retroreflector and the second radar retroreflector are configured to produce differing modulated retroreflected radar signals. 
     
     
         8 . The device of  claim 1 , wherein the radar retroreflector is configured to modulate the retroreflected signal ultrasonically. 
     
     
         9 . The device of  claim 1 , wherein the radar retroreflector includes a Van Atta retroreflector. 
     
     
         10 . The device of  claim 1 , wherein the demographic information includes at least on item selected from the list consisting of species, age, sex, and physical capabilities. 
     
     
         11 . The device of  claim 1 , wherein the demographic information includes that the user is a child. 
     
     
         12 . The device of  claim 1 , wherein the demographic information includes that the user is elderly. 
     
     
         13 . The device of  claim 1 , wherein the demographic information includes a maximum walking speed for the user. 
     
     
         14 . The device of  claim 1 , wherein the demographic information includes that the user is a pet. 
     
     
         15 . The device of  claim 14 , wherein the demographic information further includes the leash status of the pet. 
     
     
         16 . The device of  claim 1 , wherein the retroreflected radar signal is in the frequency range of about 50 to about 100 GHz. 
     
     
         17 . The device of  claim 1 , wherein the retroreflected radar signal is in the frequency range of in the frequency range of about 70 to about 85 GHz. 
     
     
         18 . A wearable radar identification system, comprising:
 an identification structure having a defined radar identification signature for radar in the frequency range of about 1 to about 300 GHz, the signature being associated with demographic information for an associated user; and   a garment incorporating the identification structure, configured to be worn by the associated user.   
     
     
         19 . The system of  claim 18 , wherein the identification structure includes an array of retroreflectors. 
     
     
         20 . The system of  claim 19 , wherein the retroreflectors of the array have positions that encode the demographic information. 
     
     
         21 . The system of  claim 18 , wherein the identification structure includes a modulated retroreflector. 
     
     
         22 . The system of  claim 21 , wherein the modulated retroreflector is configured to modulate the retroreflected signal ultrasonically. 
     
     
         23 . The system of  claim 21 , wherein the modulated retroreflector includes a modulated Van Atta array. 
     
     
         24 . The system of  claim 18 , wherein the identification structure includes a radar beacon. 
     
     
         25 . The system of  claim 24 , wherein the radar beacon is radar triggered. 
     
     
         26 . The system of  claim 18 , wherein the identification structure includes a radar reflector. 
     
     
         27 . The system of  claim 18 , wherein the demographic information includes at least one item selected from the group consisting of species, age, sex, and physical capabilities. 
     
     
         28 . The system of  claim 18 , wherein the demographic information includes that the associated user is a child. 
     
     
         29 . The system of  claim 18 , wherein the demographic information includes that the associated user is elderly. 
     
     
         30 . The system of  claim 18 , wherein the demographic information includes a maximum walking speed for the user. 
     
     
         31 . The system of  claim 18 , wherein the demographic information includes that the associated user is a pet. 
     
     
         32 . The system of  claim 31 , wherein the demographic information further includes the leash status of the pet. 
     
     
         33 . The system of  claim 18 , wherein the identification structure has a defined radar identification signature for radar in the frequency range of about 50 to about 100 GHz. 
     
     
         34 . The system of  claim 18 , wherein the identification structure has a defined radar identification signature for radar in the frequency range of about 70 to about 85 GHz. 
     
     
         35 . A method of preventing collisions, comprising:
 receiving a radar signal having a frequency of about 1 to about 300 GHz at a pedestrian location from a radar source; and   transmitting a response signal toward the radar source, wherein the response signal includes demographic information about the pedestrian, and wherein the response signal is sent without action by the pedestrian.   
     
     
         36 .- 52 . (canceled) 
     
     
         53 . A method of preventing collisions, comprising:
 sending a radar signal from an operating vehicle;   receiving a response signal from a pedestrian in response to the sent signal, the response signal including demographic information about the pedestrian; and   taking action to prevent the operating vehicle from striking the pedestrian or to mitigate the effect of striking the pedestrian.   
     
     
         54 .- 61 . (canceled)